January 15, 2025
In professional cycling, where every second counts, unforeseen incidents can derail even the most meticulously planned strategies. One of the most well known moments in recent cycling history (and even more with regards to nutrition) occurred during Stage 16 of the 2017 Giro d’Italia. Tom Dumoulin, wearing the prestigious pink jersey as the race leader, had to make an emergency stop with just 32 kilometers to go and just before the climb of the Umbrail Pass. This moment, captured on live television, is etched in cycling lore as one of the most talked-about “natural breaks” in the sport.
But how could such an incident happen to an elite athlete with access to cutting-edge nutrition and preparation? And can preparation for certain avoid such incidents? To explore this, we revisited the events of 2017 with Dumoulin and the nutritionists from Team Sunweb, whose meticulous strategies were considered revolutionary at the time.
Cycling Nutrition Before 2017: A Different World
Not long ago, nutrition was an underappreciated aspect of professional cycling. Teams typically didn’t employ full-time nutritionists, often leaving riders to decide their dietary needs on their own. While some teams recognized the potential benefits of better fuelling, a systematic approach to nutrition was rare. The concept of a team-wide, science-backed nutritional strategy was still in its infancy.Riders often relied on ad hoc advice from part-time consultants or their own intuition, leading to inconsistencies in their fuelling before, during, and after races. This lack of coordination often left riders vulnerable to underperformance or, worse, incidents like the one Dumoulin experienced.
Innovation and Progress: Team Sunweb’s Game-Changing Approach
As sport science evolved, the cycling world began to appreciate the critical role of nutrition in achieving peak performance. Team Sunweb (now Team Picnic PostNL) was at the forefront of this revolution, guided at the time by lead nutritionist Titia van der Stelt. The team transformed its nutrition program from a one-person operation to a robust department featuring multiple dieticians,chefs, and researchers. Team Sunweb didn’t have the highest budget of the peloton but decided to reserve more budget for science based guidance.
By the time Dumoulin secured the pink jersey in 2017, the team had developed cutting-edge practices, including personalized plates tailored to each rider’s specific needs. These meals accounted for a rider’s energy expenditure, carbohydrate response, body composition, and even environmental factors like extreme weather. (to adjust fluid intake to personalized sweat rates, based on prior sweat rate tests). Team Sunweb’s innovative approach soon became the gold standard in professional cycling. Also riders where able to share nutritional suggestions and the staff would help to implement.
The Build-Up to the 2017 Giro d’Italia
Grand Tour preparation begins months before the race, with teams meticulously planning menus and coordinating with hotels to ensure proper nutrition for their riders. In 2017, Team Sunweb went a step further by bringing their own chef to the Giro. This allowed the team to fine-tune meal quality and variety, ensuring riders received meals that were both performance-enhancing and moraleboosting. For example, on the evening before rest days, riders were treated to “comfort” meals like highquality burgers with homemade fries, tailored to provide both psychological relief and optimal nutrition. Such attention to detail highlighted the team’s commitment to supporting their athletes in every possible way.
The Infamous Incident: Why It Happened and Why It Matters
Despite these efforts, Dumoulin’s unexpected “sanity stop” on Stage 16 of the Giro proved that even the best-laid plans can’t eliminate every risk. The incident occurred under particularly gruelling conditions: hours of intense cycling, high altitude, and immense stress as the GC leader. These factors conspired to place enormous strain on his gastrointestinal system, leading to an urgent need to stop.
Such occurrences, while rare in their public visibility, are far from unusual in cycling. Riders consume staggering amounts of food and fluids—sometimes exceeding 8,500 kcal on a mountain stage day and ingesting 90g or more of carbohydrates per hour during a race. This level of fuelling, combined with physical exertion, can lead to gastrointestinal distress, especially in high-stress. Notably, Dumoulin was aware of these risks, having experienced similar issues in previous races.
Timing is important
An essential aspect of minimizing intestinal issues lies in timing nutrition intake. During Giro Stage 16, Dumoulin’s carbohydrate ingestion and energy expenditure were closely monitored. At the time, an intake of approximately 100g of carbohydrates per hour was considered high but necessary to sustain optimal performance in the stage’s finale. However, avoiding periods of simultaneous high carbohydrate digestion and high energy expenditure is critical, as reduced blood flow to the intestines during intense effort can exacerbate gastrointestinal distress.
For Dumoulin, products from the brand Born were likely used, offering a 2:1 oxidation rate (90g/hour). Properly managing such products during a race is vital to avoid overloading the gut. Tools like EatMyRide, now widely used by professional cyclists, help riders track and evenly distribute their intake. Notifications ensure products are fully absorbed before the next is consumed, preventing gut overload. Today, pro riders like Kwiatkowski, Mohorič, Poels, and Vollering benefit from this precise tracking. When using the head unit ‘Carbohydrate Intake/urn Balancer’ data field, you can click on each product consumed and see whether your digestion has been finished and its time to consume the next product, as well as seeing your intake needs and real-time glycogen level.
An estimation of the carbohydrate intake and expenditure for Dumoulin during stage 16 of the 2017 Giro D’Italia
A Broader Perspective: Cycling Nutrition Today
While Tom Dumoulin’s 2017 Giro triumph was, out of many things, a testament to the power of innovation and resilience, his infamous natural break is a reminder of the human element in sport. No amount of planning can account for every variable—especially in a high-pressure, high-stakes environment like a Grand Tour. Gastrointestinal issues remain a common challenge for professional cyclists, underscoring the complexity of fueling the human body for peak performance.
What did the team and Dumoulin learn?
Tom Dumoulin took the opportunity to minimize risks and asked the nutrition staff to adopt the FODMAP diet, during the preparations for the next 2018 season, which they did. The FODMAP diet is aimed at testing whether someone is sensitive to foods that contain high amounts of fermentable carbohydrates. This means not consuming many sorts of food for 10 – 14 weeks, including diary, pasta, bread, fructose sugar and glutes. This puts extra weight on the straightjacket in which a GC rider must already live.
What can it mean for you?
Dumoulin’s system was accustomed to the demands of elite cycling, but even experienced riders can face challenges when adjusting nutrition strategies abruptly. For amateur cyclists, the key takeaway is to simulate race-day nutrition during training. Gradually increasing carbohydrate intake over months of preparation can help avoid the intestinal issues often triggered by sudden dietary changes. For more detailed guidance on implementing these strategies read this article.
